Optical lenses can generally be divided into spherical lenses (SPHERICALLENS) and aspheric lenses (ASPHERICALLENS).
Spherical lens, the center range of the mirror surface is the normal imaging focal length, and the light refraction angle at the edge of the mirror surface is restricted by the shape of the spherical surface and deviates from the normal focal length track. Therefore, the acceptable imaging light range of this kind of optical lens is relatively small, and the F-number is large. As a result, the light entering the lens is relatively small.
aspherical lens, because of the convex aspherical lens, the light entering the camera through the center and edge of the mirror has the same focal length, which will make the lens The acceptable imaging light range is larger and the F number is smaller, so more light enters the camera. This result will increase the overall sensitivity. The purpose is to reduce the aberration of the optical correction lens, make the lens flatter, and reduce the magnification of the laser focusing lens. Obtain clearer, thinner, and lighter quality lenses.
Because the surface of the aspheric lens is convex, the processing cost and technology are much higher than that of the spherical lens. In order to save costs, although the photosensitive effect of aspherical lenses is better than that of spherical lenses, most of the lenses currently on the market used in the surveillance field use spherical optical lenses.
Lenses made of optical glass are optical lenses. Optical lenses can also be used in cameras, especially more expensive cameras, because the cheaper ones are now usually used with digital zoom. A better zoom, capturing more details, is still done using traditional techniques, which means using optical glass. This is one of the reasons why they are accurate even if they use almost the same technology as a basic camera.
Optical glass is made of high-purity silicon, boron, sodium, potassium, zinc, lead, magnesium, calcium, barium laser protective mirrors and other oxides mixed according to a specific formula. Melt at high temperature in platinum crucible, stir evenly with ultrasonic to remove bubbles; then slowly cool down for a long time to avoid internal stress in glass block. The cooled glass block must be measured by optical instruments to check whether the purity, transparency, uniformity, refractive index and dispersion rate meet the specifications. The qualified glass block is heated and forged to form an optical lens blank.
Optical lens refers to the use of aspherical design on the front surface of the lens, that is to say, the curvature of the lens is not a fixed value, and the optical lens will be more external than the traditional spherical lens. Thin, that is to say, under the same luminosity and refractive index, that is, the aspheric surface is designed on the inner surface of the lens or both surfaces of the lens are aspherical. This design expands the advantages of the aspheric lens, and the optical lens will be thinner. % Above; At the same time, the field of view presented by the lens will be larger.
Optical laser collimator lenses can be selected not only according to the luminosity, but also according to the form of the selected frame, optical lenses such as half-rim frames and rimless frames lenses The thickness requirements of optical lenses are relatively high. Optical lenses should not be too thick or too thin. For high-refractive-index lenses, many functions are added to the lenses when designing optical lenses. If economic conditions permit, try to choose medium-high-refractive-index lenses.
In recent years, China has gradually become an important optical glass and optical lens manufacturing base in the world. The main materials of optical lenses are a variety of optical materials such as colorless optical glass, colored optical glass, infrared optical materials, crystal materials, glassy materials and plastic materials. They have a high degree of transparency, a high degree of physical and chemical properties, and a high degree of uniformity and specificity. Precise optical constants.
The main raw material of optical lenses is optical glass, which has a higher refractive index than resin lenses. Therefore, with the same number of optical lenses, optical lenses are thinner than resin lenses. Optical lenses have relatively good light transmittance and mechanical and chemical properties, a constant refractive index, and stable physical and chemical properties. The optical lens has superior properties, is not easy to scratch, and has a high refractive index. The higher the refractive index, the thinner the lens. However, the glass is fragile and the material is heavy. When choosing a frame, you should try to choose a smaller frame to ensure the comfort of wearing.
In the process of testing and installing optical lenses, care must be taken to protect the lenses from damage and contamination. At the same time, after a new lens is installed, it should be cleaned regularly. This process is quite simple. Correct operation will extend the life of the lens and reduce costs. On the contrary, it will reduce the service life. If the lens has been contaminated but not damaged, the operator can remove it and clean it. Of course, some method should be used to avoid damage to the lens and further contamination.